MD simulation shows that severe WR mutations expose the VKOR active site for GSH reduction. (A) RMSF comparison shows that Trp59Arg mutation induces large movement of the cap domain. (B) RMSF comparison shows that Ala26Pro induces aberrant movements in the TM1 helical extension and in the anchor domain. (C) RMSF comparison shows that Leu128Arg induces movements of a loop preceding the cap domain. All MD simulations (100 ns) were repeated 3 times and similar results were obtained. (D) The structural movements expose the active site for GSH reduction. Cys132 and Cys135 are shown in green spheres and Trp59Arg, Ala26Pro, and Leu128Arg in blue. For WT and each mutant, the starting MD model is shown in light blue, pink, and red colors, and a representative conformation during the MD simulation is shown in darker colors. Full structural movements during the 100 ns simulation are shown in supplemental Movie 1. The arrows indicate the opening of the sites to which GSH may gain access. TM1e, helical extension of TM1; WT, wild-type.